Playtime: ~45 minutes
This entry was posted by one of more experienced users, so there’s no surprise that he did it very well. I may be little biased as I like this type of games, but for me it fully deserves five star score. Of course I’ve completed all the levels. It took me about 45 minutes. You can see the most difficult one in the middle of the screen.
I’m wondering how these levels were designed. I expect that there is some reversed algorithm. At least without +/- features…